In the operation of computer networks a proxy server may be used to function as an intermediary between two other computers. For example, a proxy server may function as an intermediary between a client and a second server, receiving a request from the client directed to the second server, transmitting the request to the second server, receiving a response to the request from the second server directed to the client, and transmitting the response to the client. In some cases a proxy server may specifically be a web proxy, dedicated or primarily used to act as an intermediary for web requests.
Network servers may allow for the authentication of clients. For instance, a virtual private network (VPN) server may authenticate clients to use the VPN. A virtual private network is an extension of a private network across a public network, such as the Internet, so as to allow the client access to functions of the private network.
Domain name servers may provide directory services for the domain namespace of the domain name system. A client may transmit a domain name request to a domain name server, the request comprising a domain name, and receive a numeric internet protocol (IP) address in response, the IP address corresponding to the domain name within the domain name directory.